DTSFab.com (Desert, Trail and Sand)
Automotive Powered Off Road (AKA: Buggys, Jeeps, Trucks, Etc,Etc. ) => Chassis and Suspension => Topic started by: fabr on February 13, 2014, 08:02:00 PM
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How long did it take you to eliminate nearly all of it? Usually takes a while to get close and for sand close is plenty close enough. Current build will be on road also so really good handling ,absent of "twitchiness" is a must. It took over 16 hours of manipulation of rack positioning and inner tie rod positioning to get to where I have 21" of travel and only 1/8" bumpsteer. I'm happy and damn sure glad that's over. ;D
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with my first one or last one? ;D :)
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LOL!!!!! Bad thing is that even with a suspension CAD the TR positions will be off due to minute differences in a arm mounts and minor camber/caster inaccuracies that influence the final sweet spot. I ended up 1/2" higher and 1/2" out on each TR from the CAD results.
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I let DS bang his head against the wall. I might have 1/4" froom top to bottom. Prob get some of that out but is offroad only so. I'd like to get a tag, wonder what bs1 that may be.
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If I start out with zero toe at full droop I have 1/8" total toe change over 21" On the other hand,changing nothing else other than changing toe in to 1/4" at full droop will change total toe change to 1/2 inch over 21" . It also shows how a small amount of wear in the components will greatly change the cars handling.Just an example of how sensitive any small change will be. Just an FYI,we use rack and pinion steering on most off road buggies. Rack and pinion steering will only have near perfect bumpsteer when the wheels are pointed straight forward. Any steering input to the left or right will alter,dramatically, toe numbers.
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you are absolutely correct on minute diff's or slop affecting a huge amount of bump. I do include some adjustment in the spindle up right and steering arm to make the 1/16" shim changes to adjust it out if one chooses to take the time as carl said. nothing ever holds still in the jigs or turn out EXACTLY as we shoot for but that just makes it a challenge lol the small amount you have will never be felt in the sand or on the dirt and I bet if you set it with 1/8" toe out at full droop you'll see it toe in right away in the first 1 to 2" of stroke setting you straight of course I know you already know this but for those that don't.
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ya know not only does the slop in the rack play a huge roll in bump but as the heims wear the slop in all of them adds up and setting the alignment and getting it on the money will change after the first run or two once the steel and welds have settled a little and that too can change it a touch as well. really come down to how much time one wants to spend setting it or I think the term I have been told is anal!! LMAO LMAO LMAO LMAO
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you are absolutely correct on minute diff's or slop affecting a huge amount of bump. I do include some adjustment in the spindle up right and steering arm to make the 1/16" shim changes to adjust it out if one chooses to take the time as carl said. nothing ever holds still in the jigs or turn out EXACTLY as we shoot for but that just makes it a challenge lol the small amount you have will never be felt in the sand or on the dirt and I bet if you set it with 1/8" toe out at full droop you'll see it toe in right away in the first 1 to 2" of stroke setting you straight of course I know you already know this but for those that don't.
All very true! This part especially. My front will cycle thru 26" of travel but there is no reason to use that much. At 26" (with my track width) the toe change is uncontrollable. Limited to 21" with 5" ground clearance at full bump I have ,with 1/8" static toe ,a total toe change of 1/8" in. If I try for 22" travel eferything goes to hell quickly with massive toe out that cannot be eliminated with a decent toe change/camber curve.
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YES!!!! Rack slop and initial break in of heims and rack along with the initial movement of thechassis as it settles in will make revisiting the toe issue needed soon after first run. I agree that in the sand it is very forgiving but on hardpack or asphalt,it needs to be right if running 100+ mph . Many people who run their car on the street say that the car is "twitchy" and blame it on the power assist in the car making it so. IMO,it is the simple fact it needs a proper alignment and possibly a remake of the geometry.
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Would you guys please help me with a list of progressive steps for final set up and alignment of the front end? 1st timer you see and my other buggy was set up and running when I bought it. I am doing final assembly now now can probably get close the hard way, but am hoping there is a sequence that will make it a little easier. Any help would be greatly appreciated.
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You setting alignment and toe at ride. ESP for rd and hard pack.
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yes ride height sand and hard pack.
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Sorry,didn't see this till now. i'll post some of my thoughts tomorrow sometime. It's a very involved subject actually.
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that is a difficult request with out knowing the design so I will tell you that I always jack my front end up off the ground so at full droop and set the alignment. I set caster first them camber then double check caster then double check camber once both are right then I set toe. now I'll tell you one thing out of all the front end kits I have sold that people always forget to do......center the rack before you set toe!!!!!!!!!!!! if you do not and it is off 1/8" to one side it will mess you all up. fabbr and many others know what 1/16" up or down on the steering arm does for bump so one side steering faster than the other really fooks you up lol I go out side the box on offroad norm's but I set 10* caster and 1/2* neg camber and 0 on toe. it is impossible to get an actual 0 on toe with the slop in the heims and rack even with a rack snuggy from fast ( which is a major diff on getting most the slop out!!!!! ) there is always a little. I can actually account for 3/8" toe play from the slop in heims and rack when they are a little loose. another thing and I know this will get old but if you leave the nuts and bolts loose while setting alignment you will never get right lol use some standard nuts to spin on and off and snug them all up so all of that isn't slipping back and fourth on ya. if you run limit straps then bolt them on before you set toe. I designed spindles with 1/8" wider gap than heims for my front end kits so I can pull and swap a washer rather than pulling heims for finer adjustments on all 3 points of the spindle. I can actually change 1* of caster with them. remember when you change caster you change camber and visa versa so it will take some time to get it right one. I can align my font end kits down to 0 toe change at 24" wheel travel but that's getting real picky and has to be done again after break in.
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also make sure ( if you have slop in the rack mounting point ) that the rack is level and also need to make sure your tie rods are equal length. so if they are the same length then screw the heims in all the way and screw them out 1 turn at a time each until you get it and the wheels need to be pretty close to square when you go to set caster and camber. this is all of course if the front end is built correctly and I don't care what jig you have for building a-arms they will all come out of it slightly diff. maybe not noticeable to the naked eye but slightly different so bushings become a little trickier to set but doable if done right. just take some time to do it right and once it settles it won't be bad or re-do it. good heims will make a big diff as well over steel on steel.
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Lots of great info there! Some great tips I had not thought of. I really appreciate the info!
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Well,I wrote up my method of getting the rack properly positioned as well as determining rack spreader bar tie rod positions. Only problem is I didn't hit send before leaving work. Oh well,I'll post it in the morning. I also hit upon what,IMO,are things to never,ever do. DS and I pretty much agree on things relating to front end stuff. He just takes a slightly different road to the same result.
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Great! Thanks guys.
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I always start with the basics that are extremely important . If they are ignored there will be no way to get anything correct after that.. I make a dummy bulkhead with vertical slots to allow vertical adjustment of the r&p, I also make a dummy spreader bar with slots to allow unlimited adjustment of center to center tie rod spacing. When done I make final bulkhead with correct hole positions and also tha same for the spreader bar.
1. Center rack and pinion body in car perfectly! I do not mean almost centered.
2. Center rack in car . Also perfect,not almost .
3. Accurately set camber/caster to specs @ ride heightwith desired toe .Set it,cycle suspension thru travel,recheck ,reset if necessary. At this point make absolutely certain that upper and lower outer heims are equidistant from center of car so that left and right sides are perfect mirror images of the other. This is as critical as being certain rack and spreader is centered .
4. After all that is perfect,just resign yourself to the fact it is not. rofl
5. Assuming the camber/castor curve is as desired, it is time to determine inner tie rod spacing and position in car fore/aft of spindle center line and above/below outer tie rod to outer tie rod horizon line. This is what is so tricky. It can only be done trial and error. I have a very good suspension CAD program that will design all this for you and put you in the ballpark BUT,as DS said, minor build differences will skew the inner tie rod positions from the ideal to real world needs.
6. Sooooo,how to determine inner tie rod positions? First off,take a valium. ;D ;D
7. I begin with the tie rods parallel with each other when the tie rods are level with the ground. This will make the outer rod positions and inner tie rod positions in the same vertical plane. This may or may not need to be fiddled with later.
8. I start with toe set as desired with suspension at ride height. I then cycle suspension thru full travel and recheck toe. Once again cycle thru travel and plot the toe change curve.Never check anything without cycling the suspension first. It will make a difference!
9.Now it is time to experiment with TR spacing from center I make a rack spreader with slots for this purpose. Makes life much simpler. Move inner tie rod position,reset toe,cycle,plot toe change. Repeat about a zillion times.
10.WHen it gets as good as it can be ,it is time to adjust the height. Again cycle suspension,plot toe change over full travel,adjust till as good as it gets.
11. What now? Take another Valium. drowning Start over with the inner tie rod spacing and get the toe change curve better yet and then fiddle with the height. Lastly I look at the fore/aft position of the rack itself to see if there is any room for improvement. 12. Remember ,it will be worth the effort to get it right NOW.
I want to mention that when plotting the toe change curve,it is very important that there is never any toe out . There must always be some toe in for directional stabiity especially at higher speeds on hardpack or asphalt,in the sand it is not as important but why not get it right? I try to see 1/8" toe in at full droop and see slight additional toe in at full bump.
Bear in mind the rack MUST be dead center when doing all of this and the a arms must be identical so far as picot points are concerned.
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well fabr took the time to say it better lol he is absolutly correct and 1 thing i would like to add for those with others front end designs that can't seem to get the bump out.......if it wasn't designed right in the first place you will never be able to adjust the bump out at best tone it down!!!!! there is a lot involved with getting a front end correct and time consuming if you want it right like fabbr explained but it is needed for the best end result and yet soooo many short cut it and don't care and even more don't know the difference!!
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fabbr , now I know this may be a silly question but humor me.....have you measured each wheel individually to see which one is more of the prob? did you design anti dive into the front? what is your -camber arc? just curious
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Well, heres how I'm gonna do it;
Grab
1 chair
2 valium
1 bottle of Jack Daniels
12 beers
Give 2 valium to Fabr, bottle of Jack to DS, grab chair for me and drink the 12 beer while they do it. Sure hope I have enough beer.
LMAO LMAO LMAO LMAO
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Yes,ds you nailed it. As he says,if the arm geometry is crap everything is crap no matter what you do. A proper camber/castor curve is essential and must be finalized before any bump steer elimination can be attempted. ANY change to the camber/camber will seriously affect any efforts you have made towards elimination of bump steer. In other words,DO NOT ALTER CAMBER/CASTOR AFTER SPENDING BOAT LOADS OF TIME ELIMINATING BUMP STEER!!!!!!! ;D ;D ;D ;D
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fabbr , now I know this may be a silly question but humor me.....have you measured each wheel individually to see which one is more of the prob? did you design anti dive into the front? what is your -camber arc? just curious
Yes ,I do each side individually and then check to see that the combined results add up correctly. Yes,there is usually a difference due to whatever. If built on jigs it will be minor differences but there will be differences as you and I know. Mine this time were almost non existant. ;D I got lucky.
Didn't try to eff with antidive as there is a great deal of controversy as to whether or not it is a good thing offroad. I don't really have an opinion to voice at this time as I am very wishy-washy on the subject.
Camber goes from .5-3.5 at full droopIIRC today.Don't quote me on it tho. Need to check paperwork.
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Carl,no way will that be enough beer. Better bring a 30 pack
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Ok now you guys have me spinning. I am not sure what they call my front arms as the rear part of the arm is toward the rear connecting on the side of the passenger compartment. I call it a modified A arm and I'm sure most of you call it fooked up! rofl My point is that now I see where the camber/caster will change at a different angle than a true A arm. I am seeing why you guys like a true A arm so much.
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Ya,I hate the design(no offense meant!) . You can get similar results of bump steer reduction but only if the castor/camber curve is not too wild.The process is the same.
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Ok now you guys have me spinning. I am not sure what they call my front arms as the rear part of the arm is toward the rear connecting on the side of the passenger compartment. I call it a modified A arm and I'm sure most of you call it fooked up! rofl My point is that now I see where the camber/caster will change at a different angle than a true A arm. I am seeing why you guys like a true A arm so much.
got a pic?
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Carl,no way will that be enough beer. Better bring a 30 pack
I designed it so about 20 min's and i'll have it knocked out lol whoo back up let me re-phrase that....depending on how many beers carl drank while putting it together 20 min's or so rofl rofl
fabbr I did design in 5* anti dive ( apprx 5 *) to try on just my front end and either it wasn't enough or I simply can't tell the diff between my front ends w/o brakes nd this one since none of them really took a dive when I hit the brakes lol but it does through a funny caster change in the mix which is tricky to adjust out and I can't get the toe in completely out using a full 24" of wheel stroke but now that it's all broke in ( I mean that litteraly after my near roll over in the front yard lol lol that sent all 4 wheels off the ground and nearly blew two beads lol ) I have 1/4" toe in front full droop to full bump and If I cared to spend a little more time on it I am pretty sure I could cut that in half but it doesn't effect anything that I can notice yet.
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Yes ,I do each side individually and then check to see that the combined results add up correctly. Yes,there is usually a difference due to whatever. If built on jigs it will be minor differences but there will be differences as you and I know. Mine this time were almost non existant. ;D I got lucky.
Didn't try to eff with antidive as there is a great deal of controversy as to whether or not it is a good thing offroad. I don't really have an opinion to voice at this time as I am very wishy-washy on the subject.
Camber goes from .5-3.5 at full droopIIRC today.Don't quote me on it tho. Need to check paperwork.
I set mine -.5 at full droop and achieve -3* full bump....no positive camber and I like the way it handles. I did not set the rear up for a - camber arc but have been thinking about to see if it would do any better or not. I could make a new carrier to test this w/o changing the chassis side.
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I couldn't find a pic with tie rods on but we are talking about your current v8 build aren't we? is that set up as rear steer? just kinda looks like it in the pic I saw.
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I designed it so about 20 min's and i'll have it knocked out lol whoo back up let me re-phrase that....depending on how many beers carl drank while putting it together 20 min's or so rofl rofl
fabbr I did design in 5* anti dive ( apprx 5 *) to try on just my front end and either it wasn't enough or I simply can't tell the diff between my front ends w/o brakes nd this one since none of them really took a dive when I hit the brakes lol but it does through a funny caster change in the mix which is tricky to adjust out and I can't get the toe in completely out using a full 24" of wheel stroke but now that it's all broke in ( I mean that litteraly after my near roll over in the front yard lol lol that sent all 4 wheels off the ground and nearly blew two beads lol ) I have 1/4" toe in front full droop to full bump and If I cared to spend a little more time on it I am pretty sure I could cut that in half but it doesn't effect anything that I can notice yet.
Using the suspension analyzer I found antidive was a bitch to work with when dealing with long travel. Antidive also doesn't work without the brakes .
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I set mine -.5 at full droop and achieve -3* full bump....no positive camber and I like the way it handles. I did not set the rear up for a - camber arc but have been thinking about to see if it would do any better or not. I could make a new carrier to test this w/o changing the chassis side.
I meant negative ,just as you. I always get it bassackwards. eyes brain fade I tell ya! Yes,the wheel tilts in at the top,never out. I setup my rear a arms to give a zero camber change over full travel but MAY add a bit of negative gain in bump for dirt use by making a different midboard mount. Time will tell on that though. Not a concern at this time.
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got a pic?
Working tonight I'll take a couple tomorrow night and post.
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The absolute worse bump steer/toe POS I've ever seen was the car DS fixed for a guy not too long ago. Pics on here of it. It had more toe change than wheel travel. Helen Keller could setup a front end better.
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Carl,you might want to proof read that. It appears as tho you are saying that ds built the POS. rofl LMAO He'll appreciate that. ;D ;D I think you meant the front end ds fixed for a guy,huh?
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Now thats funny!
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ya carl i repaired it i didn't build it LMAO LMAO that pos was built at the buggy shop in hutch kansas and that guy doesn't know what the hell he is doing on front ends and should either get an education or quit!! rofl
fabbr i know anti dive doesn't work with out front brakes but did forget to add that for the others that don't know. what are you thoughts on camber on rear?
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In sand ,I think zero camber is good. On hardpack or asphalt some castor is likely a good idea. It all depends on tire and grip.
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Problem with adding negative caster to the rear is the loss of travel penalty.
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So why camber on the rear? My guess is added contact area in a turn?
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On a surface with grip camber will help with tire contact. In sand there is not enough grip to deflect the tire contact patch or so the theory goes. IMO,one thing is for sure ,you do not want positive camber on any surface. Most sand cars are looking to get max travel also ,so,-camber is a no no from that standpoint .
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Carl,you might want to proof read that. It appears as tho you are saying that ds built the POS. rofl LMAO He'll appreciate that. ;D ;D I think you meant the front end ds fixed for a guy,huh?
Boy I hacked that up!! Too early for cold one (plus work) so I'm blaming it on not enough coffee. ;D ;D
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OK,since we're talking alignment,how about rear end toe in/out? I know my opinion is ,it depends on use also.
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carl rofl
sandycrack for better traction at higher speeds like running on rails.
fabbr as far as toe in the rear goes....i run 6 link rears as you know so there is a small amount of slop soooo i measure the slop and split it and then set toe in half that amount which varies but minor. as close to parallel as poss.
fabbr what do you think camber would achieve on hard pack , sand or street? what about SAI on the rear carriers like kpi for contact patch on all 3 surfaces as well like a scrub radius contact patch on front? i wonder if that would load the tires in a way to cut and carve better? just a thought.
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Big subject ,ds, one that really is only answered by defining what the handling objective is.
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your are correct but interesting topic none the less. all suspension settings are based on end use to truly tune a rail or car for ones app but many many don't know and don't do it.
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Her are a couple of pics of the front arms.
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(https://dtsfab.com/proxy.php?request=http%3A%2F%2Fwww.dtsfab.com%2Findex%2FMGalleryItem.php%3Fid%3D1511&hash=dcacd020ea257e697ef7ce6efc50d30cdc568c67)
(https://dtsfab.com/proxy.php?request=http%3A%2F%2Fwww.dtsfab.com%2Findex%2FMGalleryItem.php%3Fid%3D1510&hash=f91d1241a6995035f067e001ef173e9cc262da9b)
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your are correct but interesting topic none the less. all suspension settings are based on end use to truly tune a rail or car for ones app but many many don't know and don't do it.
+1!
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SAndy,have you checked to see that your rack travel will turn the wheels the steering angle needed? Reason I ask is because it appears to be a rather long tie rod "stem". I assume that is a fortin widespread rack?
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SAndy,have you checked to see that your rack travel will turn the wheels the steering angle needed? Reason I ask is because it appears to be a rather long tie rod "stem". I assume that is a fortin widespread rack?
Beat me to it.
How about a shot from front w/arms level. Hard to tell but rack looks high.
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I don't wish to come across too skeptical but I think this has been "eyeball" designed. I have to admit some 35 years ago I built my first steering setup from scratch including building the struts for a drag car. To put it mildly,it was a huge learning curve. I had no one to turn to for help either and the internet just did not exist. LOTS of books later I had a firm grasp of suspension design/s. Because of that I will make a couple of guesses. It appears that the pivot point of the tie rod heim on the splindle is maybe 5" or more from spindle centerline. Around 4" approx is more like it. In other words,make sure that when turning lock to lock that the outer tie rod travel matches the rack travel lock to lock. Doing so will determine the center to center dimension necessary from spindle centerline to outer tie rod heim pivot point. I would determine that before I did anything else so far as mounting the rack or building the rack spreader.
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The rack is just sitting up top not mounted. I will get some time Sunday and mount the rack back up put the tie rods on and take a couple of pics. Still have to grease the wheel bearings and then start the final alignment process, not that that has any bearing on alignment.
Fabr, if you are referencing the tie rod connecting stem on the spindle it is just long enough for the tie rod to clear the Howe power steering unit. I have not tried full stop to stop so will need to get the wheel and Sweet steering servo mounted up.
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The rack is just sitting up top not mounted. I will get some time Sunday and mount the rack back up put the tie rods on and take a couple of pics. Still have to grease the wheel bearings and then start the final alignment process, not that that has any bearing on alignment.
Fabr, if you are referencing the tie rod connecting stem on the spindle it is just long enough for the tie rod to clear the Howe power steering unit. I have not tried full stop to stop so will need to get the wheel and Sweet steering servo mounted up.
Yes,the outer tir rod heim will travel X inches lock to lock and so will the rack. Those travel numbers should very closely match. To do so will require a definite length. It appears too far from the steering axis (term I should have used earlier) to do so at this point.
From reading your post I have to ask if you are just assuming the holes in the rack that appear to be where to mount the inner tie rod heims are in the correct position ?? If so I have to also ask if you know what we are talking about when we say something about a rack spreader bar? Not trying to be a dick in any way,just trying to help and that takes us knowing if you fully understand what we are talking about. 8)
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No offense taken by me at all. I am eager to understand this for sure!
My understanding of the spreader is a bar that has the tierod mountpoints and is bolted to the rack. To me this set up is designed to use the factory bolts and believe me I could be wrong since I have never put one together. The Howe site shows 2 different billet bars one has the tierods close to center and the other has them midway to the end of the rack. Am I understanding the spreader correctly?
The rack is the Howe 2.0 wide unit they said the set up was designed for and the tierods seem to be the correct length when bolted up. Ill mount it back up and put the tierods back on and take pics and we can go from there.
Here is a pic of the way they set up the rack on the exact setup I have.
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Yes you understand what a spreader bar is. What you don't understand is why the one you have is likely not going to work. I don't think your setup is that exact setup. Same design ,yes. but not exact ,as in every little mount point is exactly the same position and spacing as the car you posted. In other words ,is your car an exact copy of the one pictured down to the most minute detail of the mounting points of everything? From your pics I don't believe it is. Now,back to the spreader bar,there is no such thing as "the right bar" for your setup unless it is an exact copy,as described above,of the car it was designed for. Therefore you,as all of us,will need to make your own. Start out by making the dummy bar as I described in an earlier post. By far the most technically difficult thing about building cars of any type is the front steering. Everything,and I mean everything ,affects everything else. If you change one parameter ,all the others change.It really is not too difficult if doing a 2-3" travel drag car but add another 20+ inches to that travel and things get difficult in a hurry.
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We all know no 2 cars will be exactly the same even off the same jig, but should be close. This car is off of the same exact jig as the one in the pic so I would think it should be very close. The bulkhead for the rack is laser cnc produced. I'll get it together and we will start from there. I am sure I will have many more questions.
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We all know no 2 cars will be exactly the same even off the same jig, but should be close. This car is off of the same exact jig as the one in the pic so I would think it should be very close. The bulkhead for the rack is laser cnc produced. I'll get it together and we will start from there. I am sure I will have many more questions.
COOL!!!!!!!!! That means you are light years ahead(if the original was designed right to start with)of the game. Do you know what the suspension specs were/are for the original you posted pic of? WHen I say specs,I mean you will have to reproduce the same camber/caster curve over the desired travel range as the original . Start with camber and caster set as the original was spec'd and post back.
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Take four pieces of square tubing drill holes in them to simulate shocks sitting at ride level and put the straps away.
You want the suspension sitting at ride level , and even side to side when you work on these matters
Check the king pin inclination angle first I think it is a problem .
If the rack sits in a straight line between the attachment points looking at it from the top and front .
And the pivots of the rack to the tie rod are on the same plane as the pivot points for the a arms where they mount to the frame you will be pretty close.
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+1 on the straps.
-1 on the tube simulating the shock. Use stands under the lower heil and be sure,as ds said earlier,that all points are snugged up to eliminate slop. You must be able to cycle the suspension thru its' full travel to check bumpsteer.
I agree on getting the rack in the ballpark tho.
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They went out of business with all the others a couple of years back and I don't know how to get in contact with them to get that info. I'll do as Pat suggested and start working it out as I go. Should start making progress with this starting Sunday. I manage a computer room and seem to be there more than home. Had I realized computer systems run 24 x 7 I might have done something different.
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http://www.amazon.com/Chassis-Engineering-Building-Performance-Handling/dp/1557880557 (http://www.amazon.com/Chassis-Engineering-Building-Performance-Handling/dp/1557880557)
Sandy crack ,
Order this book , read it and then put it in your tool box . While I have done this stuff for a living at times it is a great reference .
Instead of making the square tubes to simulate shocks like that one dumbass said take two pieces that will slide one inside the other and drill holes to simulate ride , full compression and full extension . This way you can check your suspension through cycles that are equal and unequal side to side .
But I would look at the kingpin inclination angle very first .
If you work out the steering and then have to go back and rework the spindles to get the KPI correct you will have to start over on the steering .
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Actually kpi should be called SAI(steering axis inclination). But as you said ,if the SAI is not right and therefore the scrub radius is crap nothing else will matter . All I can do is assume that this exact copy is actually exact and was correct geometry design to begin with. It very well may not be the case as ds has said before since it seems that a lot of builders do not have a clue . Buyers don't either and are duped all the time.
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I'm old
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So am I!!!! LOL!!! KPI is for kingpin straight axles such as Ford pickups. A arms use the term SAI. I'm just a bit anal ,sometimes(when it suits my purposes LOL!!!!),about this stuff.
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Great suggestion on the mock up. As for the builder we will find out I too hope he had his shit together! Now I have to get mine together! Thanks again all for the help.
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So am I!!!! LOL!!! KPI is for kingpin straight axles such as Ford pickups. A arms use the term SAI. I'm just a bit anal ,sometimes(when it suits my purposes LOL!!!!),about this stuff.
I pre-fer sai but usually say kpi because many have never heard not know the other but you are correct it is indeed sai!
sandy for some reason I can view the pics it just say make sure i'm connected to the server. with the help your getting on the this post you'll get it done just take the time and stay calm lol
remember no one is putting you down or calling anything a pos although some of us may come off this way at time and ya I know i'm one of them too. ;D
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I tried logging out and logging back in twice and still can't view the pics
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got it I had to log into photobucket for some reason. you have one of those front ends. I cannot remember the correct name but I have always called them j arms but have been corrected on that a time or two but didn't listen lol but that front end has a slight rake to the stroke of the arm. sooooo it is important that the distance in the bolt width of the rack spreader match the arms bolt on point of the bulk head and then you'll have to find the sweet spot up and down for the rack in relation to the steering arm points at the spindle. as well as the distance out from center of spindle to center of tie rod heim at the end of the steering arm so it match's at the bulk head to rack spacing. but you'll wind up high or low from equal to spindle because the of the rake the arms swing at. if you draw a straight line through the heim center on the arms they don't pivot 90* at the cradle from the bulk head but more like 22* ( guestimate from pic) so they actually swing forward and back in the motion along with up and down. that is the rake i'm talking about.
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Ditto.
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When I saw pic of rack, thought that was it mounted, so I was wrong thinking it was high.
DS, I call them J arms too. ???With this setup of arms wouldn't the rack spreader width change and get smaller the more forward you moved til it hit 0? Only way to know is to get out there and do a little playing.
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Videos always good, but at 1:10-1:15 mark watch the black cars front tires when it pulls a slight wheely.
https://www.youtube.com/watch?v=hWaT00DeUsc (https://www.youtube.com/watch?v=hWaT00DeUsc)
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I had a pretty hard time seeing it but if I saw it correctly there was massive toe out /bumpsteer going on there during droop. As said before,many builders don't have a clue and neither do buyers. I guess when those 2 meet it's a moot point whether it's right/safe or not.
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The toe out is very obvious. I fooled around with the front end early on in the build and it sure didn't seem to do that. Time will tell all as they say.
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Yep,we're wishing the best for ya!
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I know i'm not there to see it in person but not only does it toe out a crap ton if we can see it from that angle but look at the nose of the rail....does it look like it's rolled to the right but yet the left wheel has more droop in it than the right side?
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http://www.dtsfab.com/index/index.php?topic=3322.0 (http://www.dtsfab.com/index/index.php?topic=3322.0)
look at the pic......see how the tie rod ends bolt onto the rack spreader in the same width as the a-arm mounting points on the front bulk head? draw a line through the bolt heads up and down the bulk head and the heims that bolt on to the rack spreader line up through that line.
tried to find the post where bdwk corrected me on the correct name of that front end style. he also posted a link to a write up on gd.com of the pro's and con's. it is a weaker design but a space saver and has it's pro's.
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Ok step 1 and some good news. The mount points in the bulkhead for the arms are the same width as the mount point for the tie rods on the spreader. More progress as the week goes.
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Speaking of bumpsteer............
http://www.ebay.com/itm/New-Appletree-Motorcycle-Powered-Dune-Buggy-Sand-Rail-zx14r-/201037204379?forcerrptr=true&item=201037204379&pt=Dune_Buggies_Sand_Rails&hash=item2ecec04b9b&nma=true&si=KT6m8IIRRspfN9bqFAzSxFV7XAw%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557 (http://www.ebay.com/itm/New-Appletree-Motorcycle-Powered-Dune-Buggy-Sand-Rail-zx14r-/201037204379?forcerrptr=true&item=201037204379&pt=Dune_Buggies_Sand_Rails&hash=item2ecec04b9b&nma=true&si=KT6m8IIRRspfN9bqFAzSxFV7XAw%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557)
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Gotta love this part"built this car this summer for a showroom display and now it is time to go. " I bet it's time to go ...........................One look tells it all.That thing would be a terror to try to drive.
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Its a straight shooter drag only car.
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Ummm, I thought the ad said,and I quote "showroom display " . Yup,I'm pretty sure that it is a display POS. Gotta love truth in advertising. It happens so seldom. On the other hand,most sheep will only see it has a motor ,4 tires and looks cool. It's gotta be fast,great handling and safe since it looks cool. The looks cool part is just a bit dripping in Sarcasm
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Help me out here," Weighs 583 lb. " Is that even possible??? ??? ???
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Help me out here," Weighs 583 lb. " Is that even possible??? ??? ???
Only 3pcs of tube and its chromoly so it can be thinner. And its at Silverlake dunes. rofl
No way no how $12k Saw a Turbo busa Tom Pro with reverse go for $13k, way sweeter car with faster paint.
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On a side note,who the hell wants to lay down when driving in the dunes? That's just about the stupidist thing I can think of from many points not the least of which is beating the crap out of you. Always hated cars like that.
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well luckily that rail only uses 10" of travel so bump could be worse but it is refreshing to see they have stuck to there original design after all these years lol look at the 4th pic in the ad.......turning left and the right front wheel is going into what ? rofl
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On a side note,who the hell wants to lay down when driving in the dunes? That's just about the stupidist thing I can think of from many points not the least of which is beating the crap out of you. Always hated cars like that.
Layed back, pants on the ground flat biller. rofl rofl
But dont you I'd be the fastest at the drags? Its got a zx14.
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This can be done but this aint the way .
http://www.ebay.com/itm/sandrail-custom-aluminum-frame-chevy-vette-327-/131121353319?forcerrptr=true&hash=item1e87711267&item=131121353319&pt=Dune_Buggies_Sand_Rails (http://www.ebay.com/itm/sandrail-custom-aluminum-frame-chevy-vette-327-/131121353319?forcerrptr=true&hash=item1e87711267&item=131121353319&pt=Dune_Buggies_Sand_Rails)
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To each their own but no way in hell am I riding/driving that thing either.
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Well I have spent several evenings measuring and adjusting thinking I had this on the run only to back up and make some measurements and realize I have gone in a circle. So I will be starting over from the scratch. I used a caliper to verify the rack is truly centered. I decided I need a more reliable reference point front to rear so I will put 2 sticks of aluminum angle through the cab so it will stick out on the sides attached to the forward cab upright A Pillar supports. This will give me a better reference to adjust the arms forward. I feel that measuring from the center to the outside heim is pretty reliable. Sure would be easier to have had the design specs as a starting point, but I am determined.
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Update:
After spendng several evenings over the last 2 weeks I finally made progress. I have .555 change to toe in from full droop to full compression. I am still tring to get it smaller.
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Good progress but you need to get it to .25 or less as a minimum.
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I agree. Up to now I consider what I have done to be the course adjustments so now comes the fine adjustments. I have to admit I am not sure where, but am determined. I bought a laser measure to make measuring easier.
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sounds like your making good progress and are really close. fabbr is right at or under .25" change is for the best, not always possible for some builds but preferred.
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I agree. Up to now I consider what I have done to be the course adjustments so now comes the fine adjustments. I have to admit I am not sure where, but am determined. I bought a laser measure to make measuring easier.
A laser plumb bob is the best money you can spend ,use for everything on a build.
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I bought two Stanley lazer pointers with magnetic base's to set alignment on my rear and front. just measure out 3 feet infront of tires. a good way to track bump steer in an extreme measurement too. I saw enemy's and had to get a pair for myself a while back.
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sandy crack are you going to make the trek to LS for the may gathering?
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I believe I have found the resolution. I have not been able to get less than .55 regardless of what I tried. I have adjusted in all directions and even made everything worse. I played with a tool at Racing Aspirations and came up with a base set up which got me back to the .55 which is very noticeable without even measuring. I found an article authored by the guy that used to build Revenge Sand Cars, I think his name was Jason. Over on GD they used to make a lot of good comments about his building abilities, but he did screw a lot of people out of money. In the article he covered the "bump steer bracket" for the rack as the easiest way to correct for bump steer. The bracket moves the mounting points of the tie rod to the rack outside the mount points of the arms. I decided to try it and made a temp mount for the tie rod that was 1.125 wider. After cycling the arm I was amazed that the bump steer seems to be minimal now. I do have to rebuild the upper arms as the builder did not make them long enough to the front of the car. That was also part of the problem. I have a lot going on so might be a couple of weeks before I can get back to it, but will update when I get it all back together. I hope I can get it to 1/8 or less. Sorry for the long post, but I became very frustrated that I couldn't make any progress and am elated now that I seem to have made some. Time to grab a beer and celebrate!
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I will not make the May gathering. I need to use any free time I can scrounge up to work on the buggy so I can get this running this summer. I need to stay focused so I can make one of these get meets and actually have more than just a quad. Things should start picking up speed. Wahoo!
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his name is Justin and yes he did screw many out of deposits and warranties. he is still building out of his garage and that's funny he wrote an article about bump steer cause I have one of his rails that I have to drive east to see if I can get the bump out. in the sand with power steering it's fine but on the pavement it's all over the road! good to hear on your end and hope to see you one of the trips!
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I believe I have found the resolution. I have not been able to get less than .55 regardless of what I tried. I have adjusted in all directions and even made everything worse. I played with a tool at Racing Aspirations and came up with a base set up which got me back to the .55 which is very noticeable without even measuring. I found an article authored by the guy that used to build Revenge Sand Cars, I think his name was Jason. Over on GD they used to make a lot of good comments about his building abilities, but he did screw a lot of people out of money. In the article he covered the "bump steer bracket" for the rack as the easiest way to correct for bump steer. The bracket moves the mounting points of the tie rod to the rack outside the mount points of the arms. I decided to try it and made a temp mount for the tie rod that was 1.125 wider. After cycling the arm I was amazed that the bump steer seems to be minimal now. I do have to rebuild the upper arms as the builder did not make them long enough to the front of the car. That was also part of the problem. I have a lot going on so might be a couple of weeks before I can get back to it, but will update when I get it all back together. I hope I can get it to 1/8 or less. Sorry for the long post, but I became very frustrated that I couldn't make any progress and am elated now that I seem to have made some. Time to grab a beer and celebrate!
That's the rack adapter we told you about earlier in this topic.
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I will not make the May gathering. I need to use any free time I can scrounge up to work on the buggy so I can get this running this summer. I need to stay focused so I can make one of these get meets and actually have more than just a quad. Things should start picking up speed. Wahoo!
I hear you on that!!!! Keep at it,we'll meet up soon enough.